Orthogonal arterial catheter

ABSTRACT

An orthogonal arterial catheter preferably includes a hub and a cannula. The hub preferably protects the cannula from potential kinking and shearing forces because the cannula upon exiting a patient&#39;s body enters the hub. The hub preferably provides a passageway through which the hose travels to a connector piece. The connector piece preferably attaches the device to a fluid line such as an arterial line transducer. In addition, the hub preferably includes a port that provides a channel through which a guide wire or a needle may gain access to the cannula. The hub also may include appendages extending from it to suture to the patient.

This application claims the benefit of U.S. provisional Application Ser.No. 60/182,199, filed Feb. 14, 2000, which is hereby incorporated byreference.

FIELD OF THE INVENTION

The invention relates to catheters used to monitor blood pressure withinthe femoral artery of patients.

BACKGROUND OF THE INVENTION

Catheters connecting to blood vessels are used primarily to monitorblood pressure in real-time. When a catheter is inserted into thefemoral artery it is done so at a low angle such as 40 to 60 degreesabove the skin surface. As the catheter cannula obtains altitude abovethe patient's body, the cannula is attached to monitoring equipment. Theconnection point to the monitoring equipment is a place where thecatheter will at times shear away from the monitoring equipment, whichmay result in loss of blood from the patient if the catheter cannula isnot quickly removed and/or clamped by medical personnel. The likelihoodof shearing is dependent in part upon the firmness of the cannula (orhose) with a firmer cannula more likely to shear. Also, kinking of thecannula may occur, in part, because of the shallow entry angle of thecatheter into the patient and movement of the patient's limbs or thecatheter itself while obtaining blood samples.

Attempts have been made to use pediatric internal jugular catheters withthe femoral artery. This type of catheter cannula also easily shears atthe hub causing the catheter cannula to fail because it exits the hubhorizontally and then dives beneath the skin into the artery in asomewhat vertical orientation. The pediatric internal jugular catheteralso has a long soft Teflon hose, which leads to two additionalproblems. The length requires that the insertion point be some distancefrom the hub, which leads to a greater chance of kinking and otherproblems that may occur when a hose runs for an extended distanceunprotected. The second problem is that Teflon is too soft and willcollapse in on itself when blood is drawn from the catheter because ofthe applied suction forces within the hose from the syringe drawingblood. Another problem associated with catheters in general is that itis difficult to obtain accurate blood pressures readings when rightangles or kinking occurs in the hose containing the patient's blood,because the kinks and right angles cause turbulence within the bloodresiding in the cannula.

Usually a catheter is inserted using a needle within a lumen of acannula. When the needle penetrates the vessel, the blood pressure inthe vessel will cause blood to flow up the needle bore and intotranslucent tubing around the top of the needle. The practitionerverifies the penetration of the vessel by looking for blood “flashback”in the tubing. The needle is withdrawn from the catheter, and thecannula is preferably advanced within the blood vessel to a desiredposition sometimes with the aid of a guide wire.

Notwithstanding the usefulness of the existing catheters, a need existsfor a more dependable and durable catheter that easily attaches topatients and provides real-time accurate blood pressure of the patient.

SUMMARY OF THE INVENTION

This invention solves the ongoing problems of attaching a catheter to apatient and obtaining real-time accurate blood pressure. The inventionwhile addressing the problems of the prior art obtains advantages thatwere not achievable with the prior art devices.

The present invention relates to a catheter capable of being insertedinto a variety of veins and arteries as needed by medical personnel whowish and need to monitor a patient's blood pressure in real-time and/orto take regular blood samples from the patient. The invention preferablyincludes a hub and a cannula running through the hub. The hub preferablyprovides a port through which to pass a needle and an insertion wireinto the cannula and a connector at one end of the cannula/hub to attachto medical equipment. The port may also be used to insert a syringe forobtaining blood samples from the blood present within the hub. The hubpreferably includes a passageway that runs from the connector to an exitpoint through which the cannula travels. The passageway preferablyincludes a gentle bend to reduce and/or prevent turbulence. The cannulapreferably extends from the hub such that it may be inserted into apatient's blood vessel.

An object of this invention is to improve the reliability and accuracyof real-time blood pressure readings.

Another object of this invention is to produce an even and accuratetransmission of the blood pressure wave.

Another object of this invention is to lengthen the life span of aninserted catheter by protecting the catheter at the skin insertion site.

Another object of this invention is to increase the ease in which bloodsamples are taken from patients.

An advantage of this invention is a more secure attachment of thecatheter to the patient.

Another advantage of this invention is the durability of the catheterleading to a longer life span for the catheter.

Another advantage of this invention is a lower profile for the device.

Another advantage of this invention is the prevention of turbulencewithin the catheter.

Given the following enabling description of the drawings, the methodshould become evident to a person of ordinary skill in the art.

DESCRIPTION OF THE DRAWINGS

The use of cross-hatching within these drawings should not beinterpreted as a limitation on the potential materials used forconstruction of the invention. Like reference numerals in the figuresrepresent and refer to the same element or function.

FIG. 1 illustrates a side view of the preferred embodiment of theinvention.

FIG. 2 depicts a front view of the preferred embodiment of theinvention.

FIG. 3 illustrates a top view of the preferred embodiment of theinvention.

FIG. 4 depicts a side cross-section of the preferred embodiment of theinvention.

FIG. 5 illustrates a side cross-section of the preferred embodiment ofthe invention with an alternative curved passageway.

FIG. 6 depicts a side cross-section of the preferred embodiment of theinvention with another alternative curved passageway.

FIG. 7 illustrates a top view of another alternative embodiment of theinvention.

FIG. 8 depicts a top view of an alternative embodiment of the invention.

FIG. 9 illustrates a side cross-section of an alternative portconfiguration.

FIG. 10 depicts a side cross-section of another alternative embodiment.

FIG. 11 illustrates a side cross-section of catheter kit that includesthe invention.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1-6 illustrate the preferred embodiment of the invention directedto an orthogonal arterial catheter. The catheter preferably includes ahub 20 and a cannula (or hose) 40. The hub 20 preferably provides thestructure to prevent the cannula 40 from kinking on itself and/orshearing from a fluid line 60. The cannula 40 preferably provides theconduit in which blood from the patient resides.

Preferably, the cannula 40 extends sufficiently below the hub 20 suchthat it may be initially inserted into the patient at a shallow angle tothe patient's skin prior to the hub 20 being attached to the patient.Although the length of the cannula 40 preferably will allow the medicalprofessional the whole range of insertion angles. The hub preferablywill act as an indicator as to when the cannula has been insertedsufficiently, i.e., when the hub abuts the patient's skin.

The hub 20 need not have any particular shape, but preferably it has abottom surface shaped so it can rest against a patient's body withoutwobbling. The hub 20 also preferably has a shape such that a user caneasily grasp it when the cannula 40 is being installed in a patient'sbody. The illustrated hub 20 in FIGS. 4 and 6 is a hollow, substantiallyrigid member having a flat bottom surface and a curving shape on itsupper portion. More preferably, the hub 20 is in a shape of a computermouse (FIGS. 1, 4-6, and 10) or hockey puck (FIG. 11). Alternatively, ifthe hub 20 is intended to be used in a single location on a patient'sbody, the bottom surface may be contoured to match the body contourwhere it is to be installed.

The hub 20 preferably includes a passageway (or channel) 22 and a port30. Either the hub 20 or the cannula 40 will preferably include aluer-lock connector 50 that will connect to a fluid line 60 (or pressureline). The luer-lock connector 50 preferably is approximately 2 mm toapproximately 5 mm above the bottom surface of the hub 20. If the hub 20includes the luer-lock connector 50, then the luer-lock connector 50preferably includes a fitting 52 to attach to the cannula 40 topreventing leaking as illustrated, for example, in FIG. 5.Alternatively, the luer-lock connector 50 may be part of the cannula 40as illustrated, for example, in FIGS. 4 and 6 depending upon themanufacturing design chosen.

The passageway 22 preferably turns from a horizontal alignment at theluer-lock connector 50 to a vertical alignment at the exit point 28 ofthe cannula 40. In between these two points, the passageway 22preferably passes through a curved section 222 to change the flow of thehose 90 degrees as illustrated, for example, in FIGS. 4 and 6. FIGS.4-6, 10, and 11 illustrate different examples for reducing and/oreliminating turbulence resulting from orientation change and pulsationof the blood. Any curve will work that reduces, and preferablyeliminates, the turbulence that would occur if the curve was a rightangle turn with a “T” being formed by a line from the port 30 to exit 28and a second line extending from the first line to the luer-lockconnector 50. More preferably, the passageway 22 includes a verticalportion 224, a first arcuate portion 2222, a second arcuate portion2224, and a horizontal portion 226.

The port 30 preferably is directly above and aligned with the hose exit28 on the hub bottom as shown, for example, in FIGS. 4 and 6. The port30 preferably is covered with a cap (or valve) 32 that will allow accessto the port 30 and thus the cannula 40. The cap preferably is either arubber stopper 32′ or bottle cap 32 with the port 30 having thecorresponding top for the desired cap. The cap 32 may lock in place inthe port 30 using a luer-lock connection as illustrated, for example, inFIG. 9. The port 30 preferably will allow for the insertion of a guidewire or a needle into the cannula 40, which preferably is self-sealingto prevent leakage of fluid. The needle and/or the guide wire preferablyenter the cannula 40 via the port 30 to assist in inserting the cannula40 into the patient. The port 30 also preferably provides access forinserting a needle or syringe to withdraw blood from the hose fortesting without taking blood directly from one of the blood vessels ofthe patient.

At the luer-lock connector 50, the cannula 40 preferably is adapted tobe connected to an external fluid line 60 such as an arterial linetransducer. The connection between the luer-lock connector 50 and thefluid line 60 preferably may be either detachable or permanent. In thepresent example, the luer-lock connector 50 is equipped with a femaleluer-lock fitting, while the external fluid line 60 is equipped with amale luer-lock fitting for detachably mating with the female fitting.The luer-lock fittings may be reversed between the luer-lock connector50 and the fluid line 60. A few examples of other types of connectionsthat can be employed to connect the external fluid line at the luer-lockconnector include: a bayonet connection, a hose barb connection, or athreaded connection.

The hub 20 and cannula 40 may be integrally formed together such thatthe hub 20 encases the cannula 40 or the hub 20 may be reusable withdifferent cannulas 40. The hub 20 may be made of any convenientmaterial, such as a metal or plastic. Preferably, the hub 20 is aunitary piece manufactured with the passageway 22 and port 30 such thata cannula 40 with a luer-lock connector 50 may be slid into thepassageway 22 as illustrated, for example, in FIGS. 4 and 6.

An alternative is that the hub may include two or more molded sectionsthat can be assembled around the cannula and then secured to each otherin any suitable manner. This alternative embodiment is useful when thecannula 40 is inserted into the patient and then is laid over the bottomhub piece. The top hub piece then is placed over the cannula 40 andengages the lower hub piece. The preferable place to divide the hub intotwo pieces is along the passageway 22.

Another alternative is that the hub and the cannula may be integrallyformed with each other. Under any of these designs the hub need not behollow. For example, the hub 20′ may be a solid body of lightweightplastic with the passageway 22 and port 30 formed during molding orbored after formation of the solid body as illustrated in FIG. 5.

The cannula 40 preferably is made from polypropylene, polyvinylchloride, silicones, fluoropolymer, elastomeric hydrogel, polyurethane,epoxies, polyester, thermoplastics, rubber, similar flexible material,etc. More preferably, the cannula 40 is made of polyurethane. Mostpreferably, the cannula 40 is made using material capable of resealingafter being punctured by a needle. One condition for the cannulamaterial is that it will be able to withstand the vacuum forcesresulting from the drawing of blood. A second condition is that thematerial be able to be inserted into a patient's blood vessel. Thecannula 40 does not need to be long, but only of sufficient length to beinserted into a patient's blood vessel sufficiently to redirect some ofthe blood flow and then reach the fitting and/or luer-lock connector.

Alternatively, the hub 20 may also have attachment sites to secureitself to a patient as illustrated in FIGS. 7 and 8. The illustratedattachment sites are a plurality of tabs 26, which can be sutured orsewn to a patient's body to secure the hub to the patient. Each of thetabs 26 includes a hole 27 through which surgical thread can be passedto suture the hub to a patient's body. However, the attachment sites maybe a variety of things that provide a way to attach the hub to thepatient preferably through sewn suture. Examples of these types ofattachment sites are grooves 25 illustrated in FIG. 8, tunnels, ears, orholes such as eyelets. Different types of attachment sites may bepresent together on a particular hub. Alternatively, many other itemsand methods besides surgical thread can be used to immobilize the hub,such as tape, string, or straps.

An alternative structure for the port (or diverting means) 30′ isillustrated in FIG. 9. In this alternative embodiment, the port 30′ iscovered with a sealing mechanism (or preventing blood flow means) 36that preferably includes a diaphragm 938 of a resilient material (suchas an elastomer) which extends across the interior of the port 30′ andis sealed around its periphery to the inner wall of the port 30′. Theillustrated cap 32 in FIG. 9 may be omitted given the presence of thesealing mechanism 36. The diaphragm (or accessing means) 38 preferablyis equipped with a hole (or changing means) 39 through its thicknessthrough which a guide wire, a needle, or other object of relativelysmall diameter can pass.

When a guide wire or a needle is passed through the hole 39, theresilience of the diaphragm 38 presses the inner wall of the hole 39sealingly against the outer surface of the guide wire or the needle toprevent fluid from leaking from the port along exterior of the guidewire or the needle. When the needle or the guide wire is from thediaphragm 38, the resilience of the diaphragm 38 completely closes thehole 39 and seals off the port 30. To protect the diaphragm 38 againstcontamination by substances in the environment or to protect thehospital environment from contamination by fluids withdrawn from thecannula 40 through the diaphragm 38, the port 30 may be equipped with aremovable closure such as a cap 32 for covering the diaphragm 38 and theport 30 opening. In the illustrated arrangement in FIG. 9, the cap 32includes a male luer-lock fitting, which sealingly mates with a femaleluer-lock fitting on the port 30′.

An alternative structure for the hub and the hose is to have aconnection at some place other than at the luer-lock connector when theluer-lock connector is part of the hub 20. The fitting 52 discussedabove could be placed at any location within the passageway 22 after thecannula 40 enters the hub 20. However, if the fitting 52 is prior to orat the port intersection with the passageway 22, then the alternativeport 30′ should be used to prevent blood from flowing out of the hub 20and thus the patient. FIG. 10 illustrates when the fitting occurs justinside the hub.

Another alternative for the hub is removing the port. The port would beeliminated from the hub when the hub includes a bottom piece and a toppiece as described above in a prior alternative embodiment and there isno need to use the hub as the access point to draw blood.

A further alternative embodiment for the invention is to include it in acatheter kit preferably along with a needle (and/or a syringe) 60 and aguide wire 70 as illustrated in FIG. 11. Any combination of theabove-described catheter embodiments may be used in this kit. The needlepreferably will include a blood flashback compartment 62 and will behollow. Preferably, the needle will be sufficiently small to be insertedwithin the cannula 40. The guide wire 70 if included preferably will beof sufficiently small diameter to be inserted through the needle 60.

The above-described device including all of the alternative embodimentspreferably are used as follows. The first step is to connect the hub andthe cannula together if they are two separate pieces. The second step isto remove the cap from the port. As is readily apparent based on thedescription above, the first two steps may not be necessary dependingupon the design implemented. The third step preferably is to insert aneedle through the port into the cannula such that the needle willcreate a hole through the patient's skin into the selected blood vessel,which preferably is the femoral artery. The fourth step preferably is toguide the cannula into the selected blood vessel of the patient.Preferably, the medical professional will be watching for bloodflashback to stop the insertion of the needle any further.

The fifth step preferably is to insert the catheter guide wire throughthe port into the cannula to further insert the cannula into the patientpreferably after at least partial withdrawal of the needle. The fifthstep may be omitted depending upon how deep the medical professionalwishes to place the cannula into the patient. The fifth step may insteadbe the simple pushing of the cannula further in by itself without theaid of either a needle or a guide wire. The sixth step preferably is towithdraw the needle and/or catheter guide wire, and replace the cap ifone is being used. The seventh step is to connect the fluid line such asan arterial line transducer to the luer-lock connector; however, thisstep may be performed prior to this time, i.e., with the first or secondsteps. The eighth step will be to monitor the patient's blood pressurein real-time as this is typically the purpose for installing this typeof device.

This method may also include suturing the device in conjunction with theattachment sites to the patient. As discussed above when describing theattachment sites, there are alternative ways to attach this devicebesides suturing that might be used. The invention is designed such thatthe medical professional is able to insert the cannula while the hub isabove the patient's skin and out of the way.

Once the device is connected to the one of the patient's blood vessels,a blood sample may be taken using the following steps. The first step isto remove the cap, which may or may not be relevant depending on theexact design of the device used. The second step is to insert thesyringe or needle through the port into the hose and/or passageway. Thethird step is to withdraw the desired amount of blood from the hoseand/or passageway. The fourth step is to remove the syringe/needle. Thefifth step is to replace the cap removed in the first step.

This invention can be used to assist medical professionals in monitoringthe blood pressure of a patient in real-time when connected to a fluidtransducer while decreasing the risk of having a kink develop in thecannula and/or having the cannula shear its luer-lock connector. Thisinvention is also useful for providing a point from which to draw bloodfrom the patient while the catheter is in use.

Those skilled in the art will appreciate that various adaptations andmodifications of the above-described preferred embodiments can beconfigured without departing from the scope and spirit of the invention.Therefore, it is to be understood that, within the scope of the appendedclaims, the invention may be practiced and constructed other than asspecifically described herein.

We claim:
 1. A device comprising: a hub having a passageway passingtherethrough and a port in communication with the passageway, whereinthe passageway includes: a vertical portion, a first arcuate portion, asecond arcuate portion, and a horizontal portion; and wherein thevertical portion, the first arcuate portion, the second arcuate portion,and the horizontal portion form a path that provides for minimalturbulence in the flow of blood, a hose in communication with thepassageway, a connector in communication with said hose and thepassageway; and wherein the passageway travels from an opening in abottom surface of said hub to an opening in a side surface of said hub.2. The device according to claim 1, wherein the bottom surface of saidhub is formed to abut the skin of the patient.
 3. The device accordingto claim 1, wherein said hose includes said connector, and said hoselines the passageway of said hub.
 4. The device according to claim 1,further comprising a cover engaging the port of said hub.
 5. The deviceaccording to claim 1, wherein the connector connects to a fluid line,and the connector is selected from a group consisting of a luer-lockconnector, a bayonet connection, a hose barb connection, and a threadedconnection.
 6. The device according to claim 1, wherein said hubincludes means a for being attached to a patient.
 7. A method forobtaining a blood sample using the device according to claim 4 after thedevice has been installed, the method comprising: inserting a syringethrough the port into the passageway, withdrawing an amount of bloodfrom the passageway, and removing the syringe.
 8. The device accordingto claim 1, wherein said connector includes a fitting to engage saidhose, and said hub includes said connector.
 9. The device according toclaim 8, wherein said hose lines the passageway of said hub from abottom surface to said connector.
 10. The device according to claim 1,wherein said hub further includes a sealing mechanism installed in theport to seal off the port from the passageway.
 11. The device accordingto claim 10, wherein said sealing mechanism includes a resilientmaterial having a hole therethrough, the port being closed by theresilience of the sealing mechanism.
 12. A method for using the deviceof claim 1, comprising: connecting the hose and the hub together,inserting a needle through the part into the hose, guiding the hose intoa selected blood vessel of a patient using the needle, withdrawing theneedle, connecting a fluid line to the connector, and monitoring thepatients blood pressure.
 13. The method according to claim 12, furthercomprising suturing the hub to the patient.
 14. The method according toclaim 12, wherein the selected blood vessel is the femoral artery.
 15. Acatheter kit comprising: a catheter having a hub having a passagewaypassing therethrough and a port in communication with the passageway,wherein the passageway includes: a vertical portion, a first arcuateportion, a second arcuate portion, and a horizontal portion, and whereinthe vertical portion, the first arcuate portion, the second arcuateportion, and the horizontal portion form a path that provides forminimal turbulence in the flow of blood, a hose in communication withthe passageway, and a connector in communication with said hose and thepassageway; and a needle; and wherein said needle is of such diameter tobe inserted into said hose through said port.
 16. The catheter kitaccording to claim 15, further comprising a guide wire.